The present invention relates to sampling molten metal particularly steel during its production and more particularly the invention relates to the manipulation of a sampling device including particularly sampling tubes to be taken from a store and to be fastened to a lance for purposes of being lowered into the metal bath and retrieved therefrom.
The manipulation of sampling devices is a task which arises for example, in cases the temperature in the interior of molten metal being subjected to a metallurgical process is to be measured. This is particularly important during steel production. Another mode of sampling involves the removal of a certain amount of metal from the interior of the molten bath and after cooling the sample is to be analyzed for purposes of monitoring the steel making process. In each of these situations, speed and preparedness is of the essence, because the process is a running one and one wants to obtain the respective measuring results as promptly as possible it is inherent in the process that the acquired data are presented and available at a certain delay only and that delay is to be made as short as possible.
The measurements as described are being carried out repeatedly, and one needs therefore a certain number of sampling tubes. These tubes are stored conveniently and have to be removed from the store one by one, fastened to the measuring lance particularly the tip thereof and lowered and raised with respect to the metal bath. Moreover, following such a single cycle, the tube is to be removed, but the sampling device, being for example, a small container has to be removed separately and handled separately for transporting it to the laboratory. From an overall point of view, the several procedural steps and manipulation as described require a certain period of time, and it was found that between 100 and 120 seconds are needed for a complete cycle. On the other hand, a 120 second delay is generally quite long because as stated the process in the interior of the metallurgical vessel continues. Therefore, this cycle time should be made as short as possible, and particularly it should be made shorter than two minutes.
The German printed patent application 2,631,060 suggests the removal of the sampling tube, one by one, from a store and to place it into the operating range of a physically separated handling and manipulating device which receives these sampling tubes and pivots them up into the range of a holding rod being situated in the vicinity of the melting furnace or the like. These individual sampling tubes are now shifted onto the rod. A removal and retrieval device is provided separately therefrom; it operates independently from the afore mentioned tube manipulation device. The advance and retrival device is another piece of handling equipment being pivotably disposed in the range of the furnace opening so that the holding devices will be placed into the vicinity of this opening only when a sample is to be taken and removed from the furnace.
It can readily be seen that the entire known procedure of tube handling requires several transporting steps such as a step by means of which the tube is taken from the store and handled by the manipulator; another step transfers the tube from the manipulator to the pivoting device; another step requires affixing thee tubes to the measuring lance and after insertion and removal of the lance the tube has to be returned to the pivoting device. All these steps are carried out sequentially and each of them requires inherently a certain amount of time. Thus, the cycle time being the sum total of all these delays is long accordingly. As stated, manipulating a plurality of sampling tubes requires inherently a certain period of time so that a finite cycle time is inevitable. But the number of manipulating steps should be made as small as possible so that inherently a reduction of the time for some or all of these steps amounts to a shorter overall cycle time. Independently therefrom it was found that the known equipment handling the tubes require not insignificant amounts of space while on the other hand the space in and around metal processing equipment such as steel making furnace is limited.